Comment 25 for bug 365823

Run the default synaptic package handler as root from the menu system-- running something as root starts the process in the root directory not in the logged on users directory as I understand it.

This caused the /home/username folder to become owned by clamav. I'm not sure if it was the clamav-milter script although that was part of the broad ubuntu upgrade. This resulted in not being able to boot into standard gnome desktop. Gnome failsafe allows boot where you can take back ownership as the user you log on with and the problem is solved. In this case there was no ownership changes on the root (/) folder.